The present disclosure relates to a vibratory drive of a vibrating roller.
A vibrating roller is generally a construction machine and is included in the group of compaction devices in this context. With the aid of such devices it is possible to compact cohesive and noncohesive soils, base layers, anti-frost layers and asphalt. The vibrating roller generally has two roller bodies with preferably smooth drums in the interior of which a vibration unit for improving the compaction result is installed. This provides the vibrating roller with the capability of applying, in addition to its own weight, additional energy into the underlying surface.
A vibrating roller of this generic type is known from the prior art, for example according to DE 40 33 793 C2. This vibrating roller has a roller frame to which a propulsion unit is attached, and at least one drum in the interior of which an unbalance vibrator, which can make it vibrate, is arranged. The unbalance vibrator is composed of an unbalance shaft which is made to rotate by a further drive motor which is disconnected from the propulsion motor. Both the propulsion motor and the further vibrator drive motor are each embodied as hydraulic motors which are fluidically connected via a hydraulic system to a hydraulic pump which is driven by an internal combustion engine. There are also vibrating rollers in which the propulsion motor is supplied with pressure medium by at least one first hydraulic pump, and the vibrator drive motor is supplied with pressure medium by at least one further hydraulic pump.
Furthermore, hydraulic drives with recovery of braking energy in an open or closed hydraulic circuit design are known from the prior art, for example according to DE 10 2006 050 873 A or according to DE 10 2006 060 014 A1. Hydraulic drives of this type have at least one hydraulic pump which is fluidically connected to a hydraulic motor via working lines. The downstream connection of the hydraulic motor can be optionally connected to a high pressure accumulator here.
In the case of a driving mode, the hydraulic pump delivers pressure medium to the hydraulic motor, which accordingly outputs a torque to an output shaft in order to drive a machine and/or a vehicle. In the case of an overrun mode, i.e. in the case in which a torque is applied from the output shaft to the hydraulic motor, the hydraulic motor then operates as a pump and delivers pressure medium in the direction of its downstream connection. In this particular case, the high pressure accumulator is connected to the downstream connection of the hydraulic motor in order to temporarily store the pressure medium which is delivered by the hydraulic motor (now acting as a hydraulic pump).
As soon as the overrun mode changes over again into the driving mode and therefore the hydraulic motor is intended to output a torque to the output shaft again, the high pressure accumulator is connected to the upstream connection of the hydraulic pump and therefore outputs pressure medium under high pressure to the hydraulic pump. As a result, the energy consumption of the hydraulic pressure pump is reduced. In other known hydraulic drives with energy recovery, the hydraulic accumulator is connected to the upstream connection of the hydraulic motor.
Such regenerative hydrostatic drive systems are used in the prior art to recover energy from vehicles in the overrun mode. However, in vibrating rollers of the present generic type this is not possible in this form since vibrating rollers in practical use essentially do not go into an overrun mode which is relevant in terms of energy.
In view of this situation, the object of the present disclosure is to make available an energy recovery possibility for vibrating rollers of this generic type.